1. Field of the Invention
The present invention relates to domestic appliances, and particularly to a recirculating dryer that provides high energy efficient drying of laundry.
2. Description of the Related Art
Dryers are widely used in domestic and industrial environments to dry articles of clothing and other laundry. The design of dryers has not changed much since their first introduction. Most traditional dryers continuously draw in ambient air, heat the air, and circulate the heated air through a rotating drum or tumbler containing laundry to be dried. The passage of the heated air through the laundry dries the laundry, and the used air exhausts through an outlet vent to the outside. This is a very effective method of drying wet clothes, but it is very inefficient in terms of energy usage. The used hot air still contains much residual thermal energy that is continuously lost in this process. Unfortunately, most traditional dryers have no means of utilizing or recycling heat energy.
Some efforts have been made to improve energy consumption and usage in dryers. For example, microwave dryers have been introduced that basically use microwave energy to vaporize any moisture in the laundry. While efficient in terms of energy consumption compared to traditional dryers, this type of dryer cannot be used on articles containing metal, such as the buttons on jeans pants and the like, for extended periods of time because of the potential arcing that can occur, which can lead to fires. Thus, microwave drying is typically kept to a minimum, and final drying is performed by convection heating.
Another solution lies in spin dryers. These dryers are simply high rpm (rotations per minute) drums that use centrifugal force to squeeze out moisture. Much like the microwave dryer mentioned above, final drying can be performed by traditional dryers for a net reduction in energy consumption. In some cases, spin dryers are used alone.
Another example utilizes a heat exchanger and condenser integrated into the dryer. In this type of system, the exhaust hot air is circulated through the heat exchanger and cooled by ambient air or water. The water vapor is condensed and drained or collected for later disposal, and the cooled air is fed back into the drying loop. This typical condenser dryer helps reduce accumulation of excess humidity, which can have detrimental effects inside a domicile, e.g., mold. While this type of dryer consumes less energy than traditional dryers, the laundry takes longer to dry because the recirculating air is not as dry as fresh ambient air.
Thus, a recirculating dryer solving the aforementioned problems is desired.